Iraq troops in armed standoff with Kurd forces

Thousands of Iraqi troops were locked in an armed standoff with Kurdish forces in the disputed oil province of Kirkuk on Saturday as Washington scrambled to avert fighting between the key allies in the war against the Islamic State group.

The clock was ticking down to a 2300 GMT Saturday deadline that the Kurds say Baghdad has set for their forces to surrender positions they took during the fightback against the jihadists over the past three years.

Armoured cars of the Iraqi army bearing the national flag were posted on the bank of a river on the southern outskirts of the city of Kirkuk.

On the opposite bank, Kurdish peshmerga fighters were visible behind an earthen embankment topped with concrete blocks painted with the red, white green and yellow of the Kurdish flag.

"Our forces are not moving and are now waiting for orders from the general staff," an Iraqi army officer said, asking not to be identified.

The two sides have been at loggerheads since the Kurds voted overwhelmingly for independence in a September 25 referendum that Baghdad rejected as illegal.

Polling was held not only in the three provinces of the autonomous Kurdish region but also in adjacent Kurdish-held areas, including Kirkuk.

Iraqi Prime Minister Haider al-Abadi has said there can be no further discussion of the Kurds' longstanding demands to incorporate Kirkuk and other historically Kurdish-majority areas in their autonomous region until the independence vote is annulled.

He insisted on Thursday that he was "not going... to make war on our Kurdish citizens".

But thousands of heavily armed troops and members of the Popular Mobilisation Force (PMF), paramilitary units largely made up of Iran-trained Shia militias, have massed around Kirkuk.

They have already retaken a string of positions to the south of the city after Kurdish forces withdrew.

The Kurds have deployed thousands of peshmerga fighters to the area around Kirkuk itself and have vowed to defend the city "at any cost."

Just hours before the deadline, a peshmerga commander on the western front said Kurdish fighters had "taken all the necessary measures" and were "ready for a confrontation" if necessary.

If "the other side makes the mistake of advancing, we'll give them a lesson they won't forget in a hurry", Kamal Kirkuki said.